1. Field of the Invention
The present invention relates to a multipolar jack, a multipolar plug, and a structure for connecting a multipolar jack with a multipolar plug, and more particularly to a multipolar jack having a configuration in which the number of electrodes is increased by using a cylindrical portion formed on the body, a multipolar plug in which the number of electrodes is increased by using a root portion of a shaft, and a structure for connecting such a multipolar jack with such a multipolar plug.
2. Description of the Prior Art
Japanese Patent No. 2,875,617 discloses a conventional multipolar jack, and a single-head multipolar plug which serves as a counter member for the jack. The multipolar jack disclosed in the patent has four electrodes which form four electrodes inside the body. A stationary electrode which is a fifth electrode and called a mouthpiece is annularly attached to the outer periphery of a cylindrical portion of the body. A movable electrode which is a sixth electrode and elastically deformable is placed outside the stationary electrode while being separated therefrom. The multipolar plug which serves as a counter member for the multipolar jack has: a shaft comprising four contacts which are to be respectively in contact with the four electrodes of the multipolar jack; and, outside the root portion of the shaft and concentrically with the root portion, two annular connecting terminals which form fifth and sixth electrodes. The two or fifth and sixth connecting terminals are in contact with the fifth or stationary electrode and the sixth or movable electrode of the multipolar jack, respectively.
Japanese Laid-Open Patent Application No. 8-138807 discloses another conventional multipolar jack, and a single-head multipolar plug which serves as a counter member for the jack. The multipolar jack disclosed in the publication has two electrodes in two places of an outer peripheral portion of a sleeve. The multipolar plug which serves as a counter member for the multipolar jack has two annular contacts outside the root portion of a shaft and concentrically with the root portion.
Japanese Laid-Open Patent Application No. 10-335010 and Japanese Utility Model Registration No. 2,548,613 also describe a multipolar jack, a multipolar plug, etc.
In the multipolar jack disclosed in Japanese Patent No. 2,875,617, the stationary electrode which is the fifth electrode is attached to the outer periphery of the cylindrical portion formed on the body, and the movable electrode which is the sixth electrode is placed outside the stationary electrode. Therefore, the multipolar jack has a problem in that, when a five-electrode plug in which four electrodes are disposed on a shaft and a fifth or annular stationary electrode is disposed in a root portion of the shaft is connected to the multipolar jack, for example, the inner and outer faces of the fifth electrode or stationary electrode of the multipolar plug are in contact with both the stationary and movable electrodes of the multipolar jack, so that the stationary and movable electrodes may be short-circuited.
Also the multipolar jack disclosed in Japanese Laid-Open Patent Application No. 8-138807 has a problem in that, when a five-electrode plug in which four electrodes are disposed on a shaft and a fifth or annular stationary electrode is disposed in a root portion of the shaft is connected to the multipolar jack, for example, two places of the inner face of the fifth electrode or stationary electrode of the multipolar plug are in contact with two electrodes of an outer peripheral portion of a sleeve of the multipolar jack, so that the electrodes may be short-circuited.
It is an object of the present invention to provide a multipolar jack in which, in the case where two electrodes are added by using a cylindrical portion formed on the body of the multipolar jack, even when a multipolar plug having an annular electrode in a root portion of a shaft as described above is connected to the jack, the two electrodes which are added by using the cylindrical portion are not short-circuited by the annular electrode of the multipolar plug.
The present invention provides a multipolar jack having: a body; a body main portion which is formed integrally with the body; a cylindrical portion which protrudes outwardly from the body main portion; and a plurality of main electrodes which are disposed inside the body, and which are to be electrically connected to a plurality of main electrodes that are longitudinally arranged on a shaft of a multipolar plug, respectively, the multipolar plug being inserted through the cylindrical portion to a position concentrical with or substantially concentrical with the cylindrical portion, wherein the multipolar jack comprises: a large-diameter portion which is present on a side of a basal portion forming the cylindrical portion; a small-diameter portion which protrudes from a front end of the large-diameter portion; a step which is stepwise formed in a boundary between the large-diameter portion and the small-diameter portion; a first additional electrode which is placed outside the large-diameter portion, and in which a contact is positioned in the rear of the step and to be in contact with a contact on a side of an inner face of a first annular electrode disposed in a periphery of the shaft of the multipolar plug; and a second additional electrode which is placed outside the small-diameter portion, and in which a contact is positioned in front of the step and for contact with a contact on a side of an inner face of a second annular electrode concentrically disposed in a periphery of the shaft of the multipolar plug and inside the first annular electrode.
In the multipolar jack of the present invention, the distance from an axis of the cylindrical portion to the contact of the first additional electrode is longer than the distance from the axis of the cylindrical portion to the contact of the second additional electrode.
In the thus configured multipolar jack, even when a multipolar plug comprising an annular electrode (fifth electrode) in a root portion of a shaft is connected to the jack, a situation where the annular electrode is in contact with the two or first and second additional electrodes which are added by using the cylindrical portion and the two additional electrodes are short-circuited never occurs.
In the multipolar jack of the present invention, the contact of the first additional electrode is in contact with the contact on the side of the inner face of the first annular electrode disposed in a periphery of the shaft of the multipolar plug, and the contact of the second additional electrode is in contact with the contact on the side of the inner face of the second annular electrode concentrically disposed in a periphery of the shaft of the multipolar plug and inside the first annular electrode. Therefore, a multipolar plug having electrodes the number of which is equal to that of the multipolar jack can be connected to the multipolar jack.
Particularly, it is preferable to set a tip end of the first additional electrode to be positioned in the rear of the step. According to this configuration, in the case where a shaft of a multipolar plug which comprises an annular electrode (fifth electrode) in a root portion of the shaft and in which the annular electrode has an inner periphery diameter that allows the annular electrode to be fitted onto the small-diameter portion of the cylindrical portion and not to be fitted onto the large-diameter portion is inserted into the body, the annular electrode of the multipolar plug is simply inserted until the electrode abuts against the tip end of the large-diameter portion of the multipolar jack, i.e., until the electrode abuts against the step portion of the multipolar jack. Therefore, a situation where the annular electrode is in contact with the first additional electrode of the multipolar jack never occurs. Consequently, a situation does not occur where the two or first and second additional electrodes of the multipolar jack are in contact with the single annular electrode of the multipolar plug and the additional electrodes are short-circuited.
In the multipolar jack of the present invention, preferably, an outer periphery diameter of the large-diameter portion is shorter than the inner periphery diameter of the first annular electrode of the multipolar plug and larger than the inner periphery diameter of the second annular electrode, and an outer periphery diameter of the small-diameter portion is shorter than the inner periphery diameter of the second annular electrode.
In the multipolar jack of the present invention, preferably, the body main portion has a rectangular parallelepiped outer shape which extends to both lateral sides of the cylindrical portion, the first and second additional electrodes are placed on lateral sides of the cylindrical portion, and a first additional electrode attachment piece which is formed by rearward elongating the first additional electrode, and a second additional electrode attachment piece which is formed by rearward elongating the second additional electrode are fixed in both sides of the cylindrical portion to the body main portion, respectively. According to this configuration, the two or first and second additional electrodes can be attached by using the body main portion 11 which extends to the lateral sides of the cylindrical portion. Therefore, a situation where places to which the electrodes are attached protrude outside the body does not occur. This is useful for preventing an increase in the size of the multipolar jack.
In the multipolar jack of the present invention, a configuration can be employed in which four electrodes are formed by the plurality of main electrodes of the multipolar jack which are disposed inside the body, three of the main electrodes are formed by three main electrodes which are disposed inside the body main portion, and a remaining one of the main electrodes is formed by one main electrode which protrudes inside the cylindrical portion through an opening that is formed in a cylindrical wall of the cylindrical portion. According to this configuration, it is possible to obtain a six-electrode multipolar jack which can be easily miniaturized.
The multipolar plug P of the present invention has: a shaft; and a plurality of main electrodes which are longitudinally arranged on the shaft, and which are to be electrically connected to a plurality of main electrodes of a multipolar jack, respectively. Such a multipolar plug is known as a single-head multipolar plug.
As described above, in the multipolar jack of the present invention, in the case where two electrodes are added by using the cylindrical portion of the body, miniaturization can be enhanced, although, even when a multipolar plug having an annular electrode in a root portion of a shaft is connected to the jack, a situation where the two additional electrodes are short-circuited by the annular electrode does not occur.
Preferably, the multipolar plug of the present invention comprises: a first annular electrode which is disposed outside a root portion of the shaft; a second annular electrode which is concentrically placed inside and separated from the first annular electrode; a contact which is formed on a side of an inner face of the first annular electrode, and which is to be in contact with a contact of a first additional electrode of the jack; and a contact which is formed on a side of an inner face of the second annular electrode in a position shifted in an axial direction of the shaft with respect to the contact of the first annular electrode, and which is to be in contact with a contact of a second additional electrode of the jack.
In the multipolar plug of the present invention, preferably, the first annular electrode has an inner periphery diameter that allows the first annular electrode to be fitted onto the large-diameter portion of the multipolar jack, the second annular electrode has an inner periphery diameter that allows the second annular electrode to be fitted onto the small-diameter portion of the multipolar jack and not to be fitted onto the large-diameter portion, and a fitting distance of the second annular electrode with respect to the small-diameter portion of the multipolar jack is shorter than an axial length of the small-diameter portion of the multipolar jack.
According to this configuration, when the multipolar plug is connected to the multipolar jack, a situation where the second annular electrode of the multipolar plug is in contact with the first additional electrode of the multipolar jack never occurs, and hence a situation does not occur where the two or first and second additional electrodes of the multipolar jack are in contact with the second annular electrode of the multipolar plug and the additional electrodes are short-circuited.
In the multipolar plug of the present invention, preferably, the first and second annular electrodes are electrically insulated from each other by an interelectrode resin molded member which is interposed between the electrodes, and an end face of the interelectrode resin molded member is positioned in a place where the end face does not forward protrude from a front end of the second annular electrode.
In the multipolar plug of the present invention, a configuration can be employed in which four electrodes are formed by the plurality of main electrodes disposed on the shaft, and other two electrodes are formed by the first and second annular electrodes.
As described above, in the multipolar plug of the present invention, miniaturization can be easily enhanced, although two electrodes are added in the periphery of the root portion of the shaft.
The structure for connecting a multipolar jack with a multipolar plug of the present invention comprises: a multipolar jack body in which a plurality of main electrodes are longitudinally arranged inside the body; a body main portion which is formed integrally with the multipolar jack body; a cylindrical portion which forward protrudes from the body main portion; a shaft of a single-head multipolar plug which is inserted through the cylindrical portion to a position concentrical with or substantially concentrical with the cylindrical portion; a plurality of main electrodes which are longitudinally arranged on the shaft, and which are electrically connected to the plurality of main electrodes of the multipolar jack body, respectively; a large-diameter portion which is on a side of a basal portion forming the cylindrical portion; a small-diameter portion which protrudes from a front end of the large-diameter portion; a step which is stepwise formed in a boundary between the large-diameter portion and the small-diameter portion; a contact of a first additional electrode which is placed outside the large-diameter portion, and which is to be in contact in rear of the step with a contact on a side of an inner face of a first annular electrode disposed in a periphery of the shaft of the multipolar plug; and a contact of a second additional electrode which is placed outside the small-diameter portion, and which is to be in contact in front of the step with a contact on a side of an inner face of a second annular electrode concentrically disposed inside the first annular electrode.
In the connecting structure, a configuration can be employed in which a number of the main electrodes of the multipolar jack is four, and a number of the main electrodes of the multipolar plug is four.
In the connecting structure, preferably, a tip end of the first additional electrode is positioned in the rear of the step. Preferably, the first annular electrode has an inner periphery diameter that allows the first annular electrode to be fitted onto the large-diameter portion of the multipolar jack, the second annular electrode has an inner periphery diameter that allows the second annular electrode to be fitted onto the small-diameter portion of the multipolar jack and not to be fitted onto the large-diameter portion, and a fitting distance of the second annular electrode with respect to the small-diameter portion of the multipolar jack is shorter than an axial length of the small-diameter portion of the multipolar jack.
According to this connecting structure, when the multipolar plug is connected to the multipolar jack, a situation where the second annular electrode of the multipolar plug is in contact with the first additional electrode of the multipolar jack never occurs, and hence a situation where the two or first and second additional electrodes of the multipolar jack are in contact with the second annular electrode of the multipolar plug and the additional electrodes are short-circuited does not occur.
As described above, according to the structure for connecting a multipolar jack with a multipolar plug of the present invention, a multipolar jack and a multipolar plug can be connected to each other in a compact shape, and miniaturization can be enhanced, although a situation where the two additional electrodes of the multipolar jack are short-circuited by the annular electrode of the multipolar plug does not occur.